Editor Choice: Effect of Mannitol on Cerebral Blood Volume in Patients With Head Injury

Background: Mannitol has traditionally been the mainstay of medical therapy for intracranial hypertension in patients with head injury. We previously demonstrated that mannitol reduces brain volume in patients with cerebral edema, although whether this occurs because of a reduction in brain water, blood volume, or both remains poorly understood.

Objective: To test the hypothesis that mannitol acts by lowering blood viscosity leading to reflex vasoconstriction and a fall in cerebral blood volume (CBV).

Conclusion: A single bolus of 1 g/kg of 20% mannitol does not acutely lower CBV. Another mechanism, such as a reduction in brain water, may better explain mannitol’s ability to lower intracranial pressure and reduce mass effect.

From: Effect of Mannitol on Cerebral Blood Volume in Patients With Head Injury by Diringer et al.